The trade ministry said Sunday that it is seeking ways to remove non-tariff barriers set by its main trade partners on concerns they may sap Seoul's overseas shipments. China topped the list with 35 cases of non-tariff barriers, followed by the U.S. with 31 and Japan with 31, according to the trade ministry and the Korea International Trade Association (KITA). The number of the European Union's non-tariff barriers reached 29, trailed by Indonesia with 22 cases and Vietnam with 19.